1. Field of the Invention
The present invention relates to a pressure switch in which a switch provided in a body is electrically conducted with an attachment portion for attaching the body to a predetermined portion.
2. Description of the Prior Art
Conventionally, in such a pressure switch, a fixed contact of a switch is connected to the inside of a metal body which is attached to a metal attachment plate and the attachment plate is, in turn, attached to a predetermined portion, so that the switch is electrically conducted with the predetermined portion through the attachment plate.
In the thus constructed pressure switch, however, there has been a problem that it is necessary to make the body of metal so that the pressure switch is heavy in weight and expensive in cost.
Further, conventionally, in the pressure switch of this kind, a switch cover is air-tightly attached to a switch body so as to cover a connection terminal portion of the body and lead wires led out from the connection terminal portion are rendered to airtightly pass through the switch cover. The switch cover is made of a sufficiently flexible material such as rubber and is arranged such that, when the air inside the switch cover is expanded/contracted, the switch cover per se is elastically deformed so as to prevent a pressure difference from occurring between the outside and inside of the switch cover. In the case where the pressure switch is mounted at a portion of severe conditions, such as an engine room of a automotive vehicle or car, where the surrounding temperature changes extremely, there is a problem that the elastic deformation of the switch cover becomes impossible to follow the expansion/contraction of the air inside the switch cover and the moisture outside the switch cover is sucked into the switch cover through the lead wire leading-out portion, etc., so that the humidity in the switch cover becomes higher